A novel and simple method for templating hiearchical pore structure in mesoporous ceramic oxide thin films is described.

Many nanoporous Si structures, including those formed by common electrochemical etching procedures, produce a uniformly etched nanoporous surface. If the electrochemical etch rate is slowed down, details of the etch process can be explored and process parameters may be varied to test hypotheses and obtain controlled nanoporous and defect structures. For example, after electrochemical etching of heavily n-doped (R = 0.05-0.5 Omega.cm) silicon (100 single crystals at a current density of 10 mA cm(-2) in buffer oxide etch (BOE) electrolyte solution, defect craters containing textured nanopores were observed to occur in ring-shaped patterns. The defect craters apparently originate at the hydrogen/BOE bubble interface, which forms during hydrogen evolution in the reaction. The slower hydrogen evolution due to low current density and high BOE viscosity allows sufficient bubble residence time so that a high defect density appears at the bubble edges where local reaction rates are highest. Current-carrying Si-OH species are most likely responsible for the widening of the craters. Reducing the defect/doping density in silicon lowers the defect concentration and thereby the density of nanopores. Measurements of photoluminescence lifetime and intensity show a distinct feature when the few nanopores formed at the ring edges are isolated from each other. Overall features observed in the photoluminescence intensity by XPS strongly emphasize the role of surface oxide that influences these properties. Copyright (c) 2005 John Wiley & Sons, Ltd.

Thin films of cobalt silicide are widely used as metallization in very large-scale integrated electronic circuits. In this study, Co ions were deposited on Si(111) wafers by a high beam current filter metal vacuum arc deposition (FMEVAD) system. Surface silicide films were formed after annealing from 500 to 700°C for 30min. The results show that a thin CoSi2 surface layer with both a smooth surface topography and sharp interface can be achieved by annealing at 700°C. The CoSi phase and O contamination were observed in the samples that were annealed at lower temperatures.

Damage evolution and thermal recovery of 1 MeV Au 2+ irradiated samarium titanate pyrochlore (Sm 2 Ti 2 O 7 ) single crystals were studied by Rutherford backscattering spectroscopy and nuclear reaction analysis. The damage accumulation follows a nonlinear dependence on dose that is well described by a disorder accumulation model, which indicates a predominant role of defect-stimulated amorphization processes. The critical dose for amorphization at 170 and 300 K is ~0.14 dpa, and a higher dose of ~ 0.22 dpa is observed for irradiation at 700 K, which agrees with previous in-situ transmission electron microscopy (TEM) data for polycrystalline Sm 2 Ti 2 O 7 . Annealing in an 18 O environment reveals a damage recovery stage at ~ 850 K that coincides with a significant increase in 18 O exchange due to oxygen vacancy mobility. This thermal recovery stage is also consistent with the critical temperature for amorphization measured by in-situ TEM in polycrystalline samples.

Damage accumulation in Sm2Ti2O7 single crystals irradiated with Au2+ ions at 170, 300 and 700 K was studied by Rutherford backscattering spectrometry using a 2.0 MeV He+ beam along the 〈0 0 1〉 channeling direction. The relative disorder on the Sm sublattice follows a nonlinear dependence on ion fluence. The nonlinear behavior is described well by a disorder accumulation model that indicates a predominant role of a defect-stimulated amorphization process. The critical dose for amorphization at 300 K is ∼0.14 dpa, which is in good agreement with in situ transmission electron microscopy results for polycrystalline Sm2Ti2O7 irradiated with 600 keV Bi+ ions and with Gd2Ti2O7 doped with 244Cm. Despite the six orders of magnitude difference in damage rates, the good agreement between the amorphization doses in Sm2Ti2O7 at 300 K and 244Cm-doped Gd2Ti2O7 at 340 K indicates that damage accumulation at these temperatures is relatively independent of dose rate.

Microfabricated SiO2 nanotips are potentially useful as scanning tips in near-field optical microscopy and sensor related functions. We report a process in which the rounding nature of isotropic etching combined with undercutting property of Si(100) are effectively used to microfabricate laterally ordered SiO2 nanotips. Combination of excessive isotropic wet etching of thermally grown SiO2 with anisotropic etching of n-type silicon along (100) planes leads to the formation of nanotips with sharpness; 15 nm. Uniform periodic array of nanotips form due to coalescence of excessively etched SiO2 resulting in nanotips length less than or equal to the separation between the original photolithographic features. Finally, the overall process of nanotip formation is discussed by considering the roles of rapid isotropic etching of SiO2 in buffered oxide etch solution, anisotropic etching of Si(100) in KOH solution, and slow SiO2 etching in KOH solution. (C) 2003 The Electrochemical Society.

1.1. The immunological relatedness of several annelid extracellular hemoglobins and chlorocruorins was investigated using ELISAs and Western blotting to determine the binding of purine polyclonal and monoclonal antibodies to Lumbricus terrestris hemoglobin with the hemoglobins of Tubifex tubifex, Tylorrhynchus heterochaetus, Arenicola marina and Macrobdella decora and the chlorocruoins of Myxicola infundibulum and Eudistylia vancouverii.2.2. Polyclonal antibodies to Lumbricus terrestris hemoglobin bound to all the other hemoglobins and chlorocruorins. However, the titers were in all cases one to several orders of magnitude smaller than with Lumbricus terrestris hemoglobin.3.3. Polyclonal antibodies to Eudistylia vancouverii chlorocruorin bound to the hemoglobins of Lumbricus terrestris, Tubifex tubifex, Arenicola marina, Tylorrhynchus heterochaetus and Macrobdella decora.4.4. Of the nine monoclonal antibodies to Lumbricus terrestris hemoglobin isolated, two (No. 24 and No. 26) bound to the other hemoglobins and to Myxicola chlorocruorin, but the binding was again weaker than with Lumbricus hemoglobin. Antibody No. 26 also bound to Eudistylia chlorocruorin. Although antibody No. 24 appears to recognize a conformation-dependent epitope, antibody No. 26 recognizes a common epitope in each of the four subunits M, DI, D2, and T of unreduced Lumbricus hemoglobin.5.4. An additional two monoclonal antibodies to Lumbricus hemoglobin (No. 21 and No. 25) bound also only to Tubifex hemoglobin. Antibody No. 21 recognizes subunits D1 and M of Lumbricus hemoglobin and No. 25 appears to recognize a conformation-dependent epitope.

Dumping grounds in New York Bight receive very large quantities of sewage sludge. Lobsters and rock crabs collected in or near the dumping grounds sometimes show various pathological conditions of the shell and gills. In this study the histopathology of ‘shell disease’, the causative agents and its effects on respiration are discussed in connexion with a possible association with the disposal of solid wastes into the ocean.

Hot water effluent from power stations kills juvenile menhaden migrating through Long Island Sound. Since the fish sink to the bottom, losses are unrecorded or at best under-estimated. Other fish are probably also affected. Menhaden in Long Island Sound contribute to the commercial fishery off the eastern seaboard of the United States. At present the losses have little impact on the fishery, but if the projected increase in hot water discharges into the Sound materializes the consequences may be serious.